From The Laser Guidebook


Convenience dictates that the broad field of semiconductor lasers be broken up into manageable chunks, and it seems logical to group together those with wavelengths shorter than about 1.1 micrometers ( ?m). Most are based on gallium arsenide, the oldest type of semiconductor laser. Unlike longer-wavelength diode lasers, they have a wide range of applications, including compact-disk players, optical data storage, laser printers, measurement and inspection, laser pointers, and power sources for pumping other lasers. Short-wavelength lasers themselves break into distinct families, as do as some general-purpose lasers.

Short-wavelength laser diode technology has become increasingly versatile as it has matured. Mass-produced milliwatt lasers sell for a few dollars each in large quantities. Monolithic arrays can generate watts of power, and command much higher prices. Some lasers have very high modulation bandwidths for high-speed communications. Others are packaged with focusing optics to meet stringent beam-quality requirements. They employ the family of semiconductor laser structures described in Chap. 18.

New types of lasers have broadened the range of wavelengths beyond those of traditional gallium aluminum arsenide lasers. In late 1990, the shortest wavelength offered was 635 nanometers (nm) in the red, from InGaP/InGaAlP multiple-quantum-well lasers on GaAs substrates. Only one company offered that wavelength, but more were expected to follow.

At longer wavelengths, developers have made strained-layer InGaAs lasers (see Chap. 18) emitting at 980 nm. That wavelength had been sought for pumping erbium-doped fiber amplifiers (see Chap. 26) but had not been available because it was in the lattice-...

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Diode Lasers
Diode lasers use light-emitting diodes to produce stimulated emissions in the form of coherent light output. They are also known as laser diodes.
Laser Engraving and Laser Marking Machines
Laser engraving and laser marking machines use a high-powered laser to mark or scribe materials with text, images, patterns, and graduations.
Lasers are devices that produce intense beams of monochromatic, coherent radiation. The word "laser" is an acronym for Light Amplification by Stimulated Emission of Radiation.
Helium Neon Lasers
Helium neon (HeNe) lasers have an emission that is determined by neon atoms by virtue of a resonant transfer of excitation of helium. They operate continuously in the red, infrared and far-infrared regions and emit highly monochromatic radiation.
Excimer Lasers
Excimer lasers are rare-gas halide or rare-gas metal vapor lasers that produce relatively wide beams of ultraviolet laser light. They operate via the electronic transitions of molecules.

Topics of Interest

Semiconductor diode lasers with wavelengths longer than 1.1 micrometers ( ?m) are used primarily for fiber-optic communications. The only III-V material system used for commercial lasers is InGaAsP, a...

9.11.5 InGaAs Pump Lasers Obtaining longer wavelengths from lasers in the GaAs family requires adding indium to replace some of the gallium and reduce the band gap. Fabricated on GaAs substrates,...

9.11.4 Gallium Arsenide Near-Infrared Lasers The oldest and best-developed family of diode lasers have active layers of GaAlAs or GaAs and are fabricated on GaAs. They are usually called "gallium...

9.14 WHAT HAVE WE LEARNED? Semiconductor lasers are often called diode lasers or laser diodes. Diodes are two-terminal electronic devices that conduct current in one direction. Electrons in the...

9.11.3 Red Diode Lasers Although we take red diode lasers for granted today, the first diode lasers with beams easily visible to the human eye, at 670 nm, did not reach the market until the late...

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